[R] Matrix formatting - reprise

[Andy Bunn]

Given all these NA formatting replies - I have a question of my own.

I too have an object like foo.dat from the pervious posts:

foo.dat <- cbind(c(NA, 1, 2, 3, 4, 5), c(NA, NA, 0, 10 ,20, 30))

> foo.dat
     [,1] [,2]
[1,]   NA   NA
[2,]    1   NA
[3,]    2    0
[4,]    3   10
[5,]    4   20
[6,]    5   30


and I have vector I want to subtract from each column of foo.dat say:

foo.subtract <- c(0.1, 0.2, 0.3, 0.4, 0.5)

I want to perform the subtraction from foo.dat but preserve the
structure of the data. I.e.,

     [,1] [,2]
[1,]   NA   NA
[2,]  0.9   NA
[3,]  1.8 -0.1
[4,]  2.7  9.8
[5,]  3.6 19.7
[6,]  4.5 29.6

The final formatting of foo.dat has to be intact - I can't just shove
the NAs to the bottom. I tried to order the data in an apply function
but couldn't make it work.

Thanks, Andy


-----Original Message-----
From: r-help-admin at stat.math.ethz.ch
[mailto:r-help-admin at stat.math.ethz.ch] On Behalf Of Tim Sharac
Sent: Wednesday, February 12, 2003 1:42 PM
To: r-help at stat.math.ethz.ch
Subject: [R] Matrix formatting

Hi R-users:

I have a data formatting question. I have a data set that looks
something like this:

foo.dat <- cbind(c(NA, 1, 2, 3, 4, 5), c(NA, NA, 0, 10 ,20, 30))

What I have:

     [,1] [,2]
[1,]   NA   NA
[2,]    1   NA
[3,]    2    0
[4,]    3   10
[5,]    4   20
[6,]    5   30


I want to line up the columns by the first value that is not NA. Like
so:

     [,1] [,2]
[1,]    1   0
[2,]    2   10
[3,]    3   20
[4,]    4   30
[5,]    5   NA
[6,]    NA  NA

Question is: Is there an elegant way to do this without a for loop?

I tried doing this with na.omit and na.exclude without success.

The real data is many hundreds of columns and many thousands of rows.

Thanks in advance, Tim

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